The Perfect Setup - Ubuntu 6.10 Server (Edgy Eft) mail problem

I have a question about The Perfect Setup - Ubuntu 6.10 Server (Edgy Eft),
At first i want to say i really like the howto, thanks! It is very useful.
But now i have a problem, when i send mail via squirrelmail to my other email, it says: 'from: web6_*name*@example.com
I think i made a mistake and copied the text '@example.com' without
changing it to my own hostname.
Do you know what i have to change or where i can change it?

Thanks, and i hope you understand what i mean, my english is not that
good.